240 research outputs found

    Report on a collecting trip of the British Myriapod Group to Hungary in 1994

    Get PDF
    During a collecting trip participated jointly by the members of the British Myriapod Group and by Hungarian experts in 1994, 34 species of millipedes, 14 of centipedes, 8 of woodlice and 73 of spiders were recorded from Hungary. Two records of the millipede species Boreoiulus tenuis (Bigler, 1913) and Styrioiulus styricus (Verhoeff, 1896) were new to the fauna of Hungary

    From Serializable to Causal Transactions for Collaborative Applications

    Get PDF
    Serializability is the traditional consistency criterion when shared objects are accessed concurrently. Its main drawback lies in the strong synchronization constraints it imposes on execution of applications when they are run on distributed systems. In this paper we examine weake consistency criteria for computations in which accesses to shared objects are grouped to form transactions. In particular, we explore causal consistency and causal serializability for transaction based computations. These criteria turn out to be sufficient for a class of applications ( e.g., collaborative applications) and their implementation results in greater availability of data and improved performance. These criteria are formally defined and protocols implementing them are presented. We demonstrate that causal consistency allows both read and update transactions to be executed in a wait-free manner. Although write accesses in causal serializability require synchronization with other nodes, read accesses appearing in update transactions can be executed locally. This distinguishes causal serializability from serializability where synchronization is necessary for both read and write accesses of update transactions. Finally, fault-tolerance problems are addressed in the context of process crash failures

    Woodlice (Isopoda: Oniscidea) and the centipede Scutigera coleoptrata (Chilopoda) collected from Hungary by the British Myriapod Group in 1994:

    Get PDF
    Twenty-seven species of woodlice are recorded from Hungary in 1994 during a joint collecting trip undertaken by the British Myriapod Group and Hungarian experts. Five species, Armadillidium vulgare (LATREILLE, 1804), Protracheoniscus politus (C. KOCH, 1841), Trachelipus rathkii (BRANDT, 1833), Platyarthrus hoffmannseggii BRANDT, 1833 and Trachelipus nodulosus (C.KOCH, 1838), were widely recorded and accounted for 48% of the 1,200 specimens collected. The first Hungarian record of Trichoniscus provisorius RACOVITZA, 1908 is given. Records of the apparently rare species, including Trichoniscus steinboecki VERHOEFF, 1931, Hyloniscus vividus (C. KOCH, 1841), Haplophthalmus montivagus VERHOEFF, 1941 and Lepidoniscus minutus (C. KOCH, 1838) are presented for semi-natural habitats. It is suggested that some of these species, particularly H. montivagus, may have been over looked and consequently may be under recorded. Other apparently rare species, including Androniscus roseus (C. KOCH, 1838), Oniscus asellus Linnaeus, 1758, Porcellio spinicornis SAY, 1818 and Armadillidium nasatum BUDDE-LUND, 1885 are recorded from synanthropic sites. The potential value of synanthropic habitats for Oniscidea is highlighted. A record for the centipede, Scutigera coleoptrata LINNAEUS, 1758 is given

    How children eat may contribute to rising levels of obesity children's eating behaviours: An intergenerational study of family influences

    Get PDF
    The term ‘obesogenic environment’ is rapidly becoming part of common phraseology. However, the influence of the family and the home environment on children's eating behaviours is little understood. Research that explores the impact of this micro environment and intergenerational influences affecting children's eating behaviours is long overdue. A qualitative, grounded theory approach, incorporating focus groups and semi-structured interviews, was used to investigate the family environment and specifically, the food culture of different generations within families. What emerged was a substantive theory based on ‘ordering of eating’ that explains differences in eating behaviours within and between families. Whereas at one time family eating was highly ordered and structured, typified by the grandparent generation, nowadays family eating behaviours are more haphazard and less ordered, evidenced by the way the current generation of children eat. Most importantly, in families with an obese child eating is less ordered compared with those families with a normal weight child. Ordering of eating' is a unique concept to emerge. It shows that an understanding of the eating process is crucial to the development and improvement of interventions targeted at addressing childhood obesity within the family context

    Ion microscopy based on laser-cooled cesium atoms

    Get PDF
    We demonstrate a prototype of a Focused Ion Beam machine based on the ionization of a laser-cooled cesium beam and adapted for imaging and modifying different surfaces in the few-tens nanometer range. Efficient atomic ionization is obtained by laser promoting ground-state atoms into a target excited Rydberg state, then field-ionizing them in an electric field gradient. The method allows obtaining ion currents up to 130 pA. Comparison with the standard direct photo-ionization of the atomic beam shows, in our conditions, a 40-times larger ion yield. Preliminary imaging results at ion energies in the 1–5 keV range are obtained with a resolution around 40 nm, in the present version of the prototype. Our ion beam is expected to be extremely monochromatic, with an energy spread of the order of the eV, offering great prospects for lithography, imaging and surface analysis

    Histological and immunohistochemical investigation on ovarian development and plasma estradiol levels in the swordfish (<i>Xiphias gladius</i> L.)

    Get PDF
    The paper reports a histological and immunohistochemical description of oocyte growth and ultrastructural aspects of zona radiata (ZR) formation as well as the relationship between plasma estradiol-17&#x03B2;, (E2 ) levels and ovarian development in swordfish (Xiphias gladius L.) from the Mediterranean Sea. Ovaries were inactive during March to mid April; maturation occurred during late April to June and spawning in June and July. Zona radiata formation starts, as Pas positive material, in oocytes at the lipid stage. In this stage a deposit of electrondense material between oolemma and follicular cells appears. In the cortical alveoli stage and through the early vitellogenic stage, the deposition of a moderately electrondense material occurred on the inner side of the ZR. Finally, in late vitellogenic oocytes a third layer, made of microfibrillar material, appeared. The immunohistochemical analyses revealed that the initial internalisation of hepatic zona radiata proteins (Zrp) in the swordfish oocyte starts before the uptake of vitellogenin (Vtg) and that it is associated with the low previtellogenic E2 plasma levels, while a significant E2 increase in plasma is associated with the beginning of Vtg uptake. This would appear to confirm the hypothesis that the differential and sequential induction of zonagenesis and vitellogenesis may reflect a general feature of teleost oogenesi

    Social cues in the expression of sequential alternative reproductive tactics in young males of the peacock blenny, Solaria pavo

    Get PDF
    Phenotypic change in response to variation in environmental cues has been widely documented in fish. Transitions in social dominance, in particular, have been shown to induce a rapid switch in reproductive phenotypes in many species. However, this effect has been mainly studied in adults and focused on behavioural transitions. The way social cues constraint the phenotypic development of juveniles remains poorly studied in fish. We tested the importance of social dominance and density in the phenotypic development of juveniles of the peacock blenny Solaria pavo. This species shows sequential male alternative reproductive tactics. In the first breeding season males can reproduce as nest-holders or as parasitic males (female-mimicking), or postpone reproduction; from the following season afterwards all males reproduce as nest-holders. Parasitic males have relatively larger testes that lack a testicular gland, present in the testes of nest-holders. The testicular gland is the main source of androgens in the testes and accordingly nest-holders have higher circulating androgen levels. In addition, exogenous androgen administration to parasitic males promotes the development of secondary sexual characters (SSC) only present in nest-holders such as a head crest and an anal gland. We raised juveniles under a high or low-density treatment and monitored social interactions for 1 month. No significant effect of density on the development of juvenile males was detected. However, within each replicate, the relative body size of juvenile males at the beginning of the experiment determined their dominance status, with dominant males developing towards the nest-holder morphotype. Dominant males engaged in more nest defence behaviour, showed larger testicular glands, had higher levels of 11-ketotestosterone (11-KT) and testosterone (T) and developed more SSC, as compared to subordinate males. However, these effects of social dominance were moderated by body condition as only dominant males in good body condition developed SSC. The effect of social dominance and of the area of the testicular gland on the development of SSC was mediated by 11-KT and on the expression of nest defence behaviour by T. Interestingly, in spite of the higher androgen levels and more pronounced morphologic development of SSC in dominant individuals, gonadal development was independent of social dominance and most fish still had underdeveloped testis at the end of the experiment. In conclusion, social dominance promoted the development of the testicular gland, an increase in circulating androgen levels and the development of SSC, but did not promote testicular development. This suggests a dissociation of mechanisms underlying sexual maturation and the expression of male reproductive traits. This dissociation seems to be the key for the occurrence of female-mimicking males in this species, which are sexually mature despite lacking the SSC typical of nest-holdets. (C) 2012 Elsevier Inc. All rights reserved.R&D Units Plurianual Program (R&D unit) from the Portuguese Foundation for Science and Technology (FCT) [331/2001]; FCT [SFRH/BD/6502/2001]; [POCTI/BSE/38395/2001]; [PTDC/MAR/71351/2006]info:eu-repo/semantics/publishedVersio

    Constraint Based System-Level Diagnosis of Multiprocessors

    Get PDF
    Massively parallel multiprocessors induce new requirements for system-level fault diagnosis, like handling a huge number of processing elements in an inhomogeneous system. Traditional diagnostic models (like PMC, BGM, etc.) are insufficient to fulfill all of these requirements. This paper presents a novel modelling technique, based on a special area of artificial intelligence (AI) methods: constraint satisfaction (CS). The constraint based approach is able to handle functional faults in a similar way to the Russel-Kime model. Moreover, it can use multiple-valued logic to deal with system components having multiple fault modes. The resolution of the produced models can be adjusted to fit the actual diagnostic goal. Consequently, constrint based methods are applicable to a much wider range of multiprocessor architectures than earlier models. The basic problem of system-level diagnosis, syndrome decoding, can be easily transformed into a constraint satisfaction problem (CSP). Thus, the diagnosis algorithm can be derived from the related constraint solving algorithm. Different abstraction leveles can be used for the various diagnosis resolutions, employing the same methodology. As examples, two algorithms are described in the paper; both of them is intended for the Parsytec GCel massively parallel system. The centralized method uses a more elaborate system model, and provides detailed diagnostic information, suitable for off-line evaluation. The distributed method makes fast decisions for reconfiguration control, using a simplified model. Keywords system-level self-diagnosis, massively parallel computing systems, constraint satisfaction, diagnostic models, centralized and distributed diagnostic algorithms

    Development of a 2,4-diaminothiazole series for the treatment of human African trypanosomiasis highlights the importance of static-cidal screening of analogues

    Get PDF
    While treatment options for human African trypanosomiasis (HAT) have improved significantly, there is still a need for new drugs with eradication now a realistic possibility. Here, we report the development of 2,4-diaminothiazoles that demonstrate significant potency against Trypanosoma brucei, the causative agent of HAT. Using phenotypic screening to guide structure-activity relationships, potent drug-like inhibitors were developed. Proof of concept was established in an animal model of the hemolymphatic stage of HAT. To treat the meningoencephalitic stage of infection, compounds were optimized for pharmacokinetic properties, including blood-brain barrier penetration. However, in vivo efficacy was not achieved, in part due to compounds evolving from a cytocidal to a cytostatic mechanism of action. Subsequent studies identified a nonessential kinase involved in the inositol biosynthesis pathway as the molecular target of these cytostatic compounds. These studies highlight the need for cytocidal drugs for the treatment of HAT and the importance of static-cidal screening of analogues
    corecore